get the autozone rechill kit or whatever its called. just did it on my moms highlander, and it made alot of diff and its pretty easy to do as well. the weird thing about my car was that i just had my compressor replaced and i had too much frion and it wouldnt get cold at all, when some was release to the proper level, that ish is cold as hell now. so i would try the 30 dollar kit, if it works, it will def be worth it.